I'm not a studio expert, and am struggling to figure out what is causing vertical stripes/banding on my paper backdrops when using strobes. Color or white, doesn't matter. I'm using the flashpoint/godox ad600 strobe with HSS turned on and shooting (in my attached example) at 1/1250th and ISO 100. This has happened to me numerous times now, and I haven't been able to detect a pattern yet. I haven't tried turning off Electronic Front Curtain yet, but will next time. It's only noticeable on paper backdrops (or maybe any plain surface), but not on my subjects.